Multi-pump driven single-motor hydro-mechanical hybrid transmission device and control method thereof

ABSTRACT

A multi-pump driven single-motor hydro-mechanical hybrid transmission device includes an input shaft, a planetary gear split mechanism, a hydraulic transmission system, a planetary gear convergence mechanism, and an output shaft. The input shaft is connected to the hydraulic transmission system and the planetary gear convergence mechanism through the planetary gear split mechanism. The hydraulic transmission system and the planetary gear convergence mechanism are both connected to the output shaft. The hydraulic transmission system includes a multi-pump driving mechanism, a fixed displacement motor mechanism, and a hydraulic transmission output mechanism. The multi-pump driving mechanism is connected to the fixed displacement motor mechanism. The fixed displacement motor mechanism is connected to the planetary gear convergence mechanism and is connected to the output shaft through the hydraulic transmission output mechanism.

TECHNICAL FIELD

The present invention relates to a transmission device and a controlmethod thereof, and in particular, to a multi-pump driven single-motorhydro-mechanical hybrid transmission device and a control method thereofwhich take both speed regulation range and speed regulation accuracyinto account and belong to the technical field of vehicle transmission.

BACKGROUND

Hydraulic transmission that features flexibility is suitable forstartup, hydro-mechanical transmission that features efficient steplessspeed regulation is suitable for operation, and mechanical transmissionthat features efficient speed variation is suitable for transfer. Ahydro-mechanical hybrid transmission device integrating hydraulictransmission, hydro-mechanical transmission, and mechanical transmissionhas high application values.

Hydro-mechanical transmission features both stepless speed regulationand efficient speed variation, which directly determines the performanceof a transmission device. A hydro-mechanical hybrid transmission devicecan implement efficient stepless speed variation by improving designschemes and design parameters of a split mechanism, a convergencemechanism, a mechanical transmission mechanism, and a hydraulictransmission mechanism. For example, hydro-mechanical transmissionbecomes diversified through combination of planetary gear split andplanetary gear convergence manners, gears are increased by replacing asimple mechanical transmission mechanism with a multi-speed gearbox, andthe accuracy of a displacement ratio is improved and the range thereofis expanded by adding functions of the hydraulic transmission mechanism.In short, a hydro-mechanical hybrid transmission device that integratesmultiple transmission types and has multiple modes is a feasiblesolution for improving the performance of such amechanical-electrical-hydraulic integration system.

SUMMARY Objective of the Invention

To eliminate the defects in the prior art, the present inventionprovides a multi-pump driven single-motor hydro-mechanical hybridtransmission device and a control method thereof. The present inventionintegrates hydraulic transmission, hydro-mechanical transmission, andmechanical transmission, wherein hydro-mechanical transmission issubdivided into hydro-mechanical split transmission and hydro-mechanicalconvergence transmission, and employs a multi-pump driven single-motorhydraulic system to implement functions such as multi-mode forward orreverse low-speed fine regulation and high-speed coarse regulation.

Technical Solution

A multi-pump driven single-motor hydro-mechanical hybrid transmissiondevice includes an input shaft, a planetary gear split mechanism, ahydraulic transmission system, a planetary gear convergence mechanism,and an output shaft, wherein the input shaft is connected to thehydraulic transmission system and the planetary gear convergencemechanism through the planetary gear split mechanism, and the hydraulictransmission system and the planetary gear convergence mechanism areboth connected to the output shaft; the hydraulic transmission systemincludes a multi-pump driving mechanism, a fixed displacement motormechanism, and a hydraulic transmission output mechanism, wherein themulti-pump driving mechanism is connected to the fixed displacementmotor mechanism, the fixed displacement motor mechanism is connected tothe planetary gear convergence mechanism, and the fixed displacementmotor mechanism is connected to the output shaft through the hydraulictransmission output mechanism. The present invention is a multi-modehydro-mechanical hybrid transmission device that integrates hydraulictransmission, hydro-mechanical transmission, and mechanical transmissionand meets the requirements of different working conditions; themulti-pump driven single-motor hydraulic system is employed to meet therequirements of different working conditions such as the directionchange of an input speed of a pump and the change of a displacementratio and the direction related thereto; and the system where multiplepumps work in turn can be used to obtain multiple flow combinations andprolong the use and maintenance cycle of the hydraulic system.

Preferably, to adapt to inputs in different directions of a hydraulicpump, the multi-pump driving mechanism includes two groups of variabledisplacement pump driving mechanisms that are connected in parallel andhave opposite input directions, wherein the variable displacement pumpdriving mechanisms include a first forward input variable displacementpump driving mechanism, a second forward input variable displacementpump driving mechanism, a first reverse input variable displacement pumpdriving mechanism, and a second reverse input variable displacement pumpdriving mechanism, a reversing valve V₄ is arranged between themulti-pump driving mechanism and the fixed displacement motor mechanism.

Preferably, to implement collaborative control of the variabledisplacement pump driving mechanism, the first forward input variabledisplacement pump driving mechanism includes a variable displacementpump P₁, a check valve V₃₁, a pilot-operated relief valve V₂₁, and asolenoid valve V₁₁, wherein the solenoid valve V₁₁ controls a controlpressure of the pilot-operated relief valve V₂₁, and the variabledisplacement pump P₁ is connected to the reversing valve V₄ through thecheck valve V₃₁;

the second forward input variable displacement pump driving mechanismincludes a variable displacement pump P₂, a check valve V₃₂, apilot-operated relief valve V₂₂, and a solenoid valve V₁₂, wherein thesolenoid valve V₁₂ controls a control pressure of the pilot-operatedrelief valve V₂₂, and the variable displacement pump P₂ is connected tothe reversing valve V₄ through the check valve V₃₂;

the first reverse input variable displacement pump driving mechanismincludes a variable displacement pump P₃, a check valve V₃₃, apilot-operated relief valve V₂₃, and a solenoid valve V₁₃, wherein thesolenoid valve V₁₃ controls a control pressure of the pilot-operatedrelief valve V₂₃, and the variable displacement pump P₃ is connected tothe reversing valve V₄ through the check valve V₃₃;

the second reverse input variable displacement pump driving mechanismincludes a variable displacement pump P₄, a check valve V₃₄, apilot-operated relief valve V₂₄, and a solenoid valve V₁₄, wherein thesolenoid valve V₁₄ controls a control pressure of the pilot-operatedrelief valve V₂₄, and the variable displacement pump P₄ is connected tothe reversing valve V₄ through the check valve V₃₄.

To meet the requirements of low-speed fine regulation and high-speedcoarse regulation in each mode, the displacement adjustment range andthe input direction of each variable displacement pump in the variabledisplacement pump driving mechanism are different, and the correspondingcheck valve, pilot-operated relief valve, and solenoid valve havedifferent parameters.

Preferably, to implement hybrid transmission of mechanical transmissionand hydraulic transmission, a jackshaft is arranged between theplanetary gear split mechanism and the planetary gear convergencemechanism;

the planetary gear split mechanism includes a split mechanism front-sungear, a split mechanism front-planet carrier, a split mechanism rear-sungear, a split mechanism rear-planet carrier, and a split mechanismshared ring gear, wherein the input shaft is connected to the splitmechanism front-sun gear and the split mechanism rear-planet carrier; aclutch C₁ is arranged between the split mechanism rear-planet carrierand the split mechanism rear-sun gear; a clutch C₂ is arranged betweenthe split mechanism front-planet carrier and the jackshaft; a clutch C₃is arranged between the split mechanism rear-sun gear and the jackshaft;and a clutch C₄ is arranged between the split mechanism shared ring gearand the hydraulic transmission system;

the planetary gear convergence mechanism includes a convergencemechanism shared sun gear, a convergence mechanism front-planet carrier,a convergence mechanism front-ring gear, a convergence mechanismrear-planet carrier, and a convergence mechanism rear-ring gear, whereinthe jackshaft is connected to the convergence mechanism front-planetcarrier, and the convergence mechanism front-planet carrier is connectedto the convergence mechanism rear-ring gear; a clutch C₅ is arrangedbetween the jackshaft and the convergence mechanism shared sun gear; aclutch C₆ is arranged between the convergence mechanism front-ring gearand the output shaft; and a clutch C₇ is arranged between theconvergence mechanism rear-planet carrier and the output shaft; a clutchC₈ is arranged between the hydraulic transmission output mechanism andthe output shaft;

a brake B₁ is arranged between the fixed displacement motor mechanismand the hydraulic transmission output mechanism.

Preferably, to implement control over multi-pump driven single-motorhydro-mechanical hybrid transmission, a control method of the multi-pumpdriven single-motor hydro-mechanical hybrid transmission device is asfollows:

switching among forward or reverse and high or low speed transmissionmodes of four transmission types including hydraulic transmission,hydro-mechanical split transmission, hydro-mechanical convergencetransmission, and mechanical transmission is implemented throughselection of the clutches, the brake, and the variable displacementpumps and combination control of the reversing valve;

in hydraulic transmission, the clutch C₁, the clutch C₄, and the clutchC₈ are engaged while the clutch C₂, the clutch C₃, the clutch C₅, theclutch C₆, the clutch C₇, and the brake B₁ are disengaged; power passesthrough the input shaft, the planetary gear split mechanism, and thehydraulic transmission system and is output from the output shaft; whenthe clutch C₁ is engaged, the split mechanism rear-planet carrier andthe split mechanism rear-sun gear of the planetary gear split mechanismare interlocked, the split mechanism rear-planet carrier and the splitmechanism rear-sun gear rotate as a whole, and power is transmittedthrough the split mechanism shared ring gear to the clutch C₄; and whenthe clutch C₄ is engaged, power is transmitted through the clutch C₄ tothe multi-pump driving mechanism, the fixed displacement motormechanism, and the hydraulic transmission output mechanism of thehydraulic transmission system, and is finally transmitted through theclutch C₈ and output from the output shaft;

in hydro-mechanical split transmission, the clutch C₄ and the clutch C₅are engaged while the clutch C₁, the clutch C₈, and the brake B₁ aredisengaged; power passes through the input shaft to the planetary gearsplit mechanism and is split at the planetary gear split mechanism intothe hydraulic transmission system and the jackshaft, and the two partsof the power are converged at the planetary gear convergence mechanismand then output from the output shaft;

in hydro-mechanical convergence transmission, the clutch C₁ and theclutch C₄ are engaged while the clutch C₅, the clutch C₈, and the brakeB₁ are disengaged; power passes through the input shaft to the planetarygear split mechanism and is split at the planetary gear split mechanisminto the hydraulic transmission system and the jackshaft, and the twoparts of the power are converged at the planetary gear convergencemechanism and then output from the output shaft;

in mechanical transmission, the clutch C₁ and the brake B₁ are engagedwhile the clutch C₄, the clutch C₅, and the clutch C₈ are disengaged,and the reversing valve V₄ is in a middle position; power sequentiallypasses through the input shaft, the planetary gear split mechanism, thejackshaft, and the planetary gear convergence mechanism and is thenoutput from the output shaft.

Preferably, to implement staged speed regulation and forward switchingof hydraulic transmission, in hydraulic transmission, the reversingvalve V₄ is switched to a right position during forward transmission;the reversing valve V₄ is switched to a left position during reversetransmission; the first reverse input variable displacement pump drivingmechanism is switched on during low-speed fine regulation; the secondreverse input variable displacement pump driving mechanism is switchedon during medium-speed regulation; and the first reverse input variabledisplacement pump driving mechanism and the second reverse inputvariable displacement pump driving mechanism are both switched on duringhigh-speed coarse regulation.

Preferably, to implement staged speed regulation and forward switchingof hydro-mechanical split transmission, in hydro-mechanical splittransmission, the reversing valve V₄ is switched to the right position;the clutch C₃ is engaged and the clutch C₂ is disengaged during forwardtransmission; the clutch C₂ is engaged and the clutch C₃ is disengagedduring reverse transmission; the clutch C₇ is engaged and the clutch C₆is disengaged during low-speed fine regulation; the clutch C₆ is engagedand the clutch C₇ is disengaged during high-speed coarse regulation; thesecond reverse input variable displacement pump driving mechanism isswitched on during forward low-speed fine regulation; the first reverseinput variable displacement pump driving mechanism and the secondreverse input variable displacement pump driving mechanism are bothswitched on during forward high-speed coarse regulation; the secondforward input variable displacement pump driving mechanism is switchedon during reverse low-speed fine regulation; and the first forward inputvariable displacement pump driving mechanism and the second forwardinput variable displacement pump driving mechanism are both switched onduring reverse high-speed coarse regulation.

Preferably, to implement staged speed regulation and forward switchingof hydro-mechanical convergence transmission, in hydro-mechanicalconvergence transmission, the reversing valve V₄ is switched to theright position, the clutch C₃ is engaged, and the clutch C₂ isdisengaged during forward transmission; the reversing valve V₄ isswitched to the left position, the clutch C₂ is engaged, and the clutchC₃ is disengaged during reverse transmission; the first reverse inputvariable displacement pump driving mechanism is switched on, the clutchC₇ is engaged, and the clutch C₆ is disengaged during low-speed fineregulation; and the first reverse input variable displacement pumpdriving mechanism and the second reverse input variable displacementpump driving mechanism are both switched on, the clutch C₆ is engaged,and the clutch C₇ is disengaged during high-speed coarse regulation.

Preferably, to implement staged speed regulation and forward switchingof mechanical transmission, in mechanical transmission, the clutch C₃ isengaged and the clutch C₂ is disengaged during forward transmission; theclutch C₂ is engaged and the clutch C₃ is disengaged during reversetransmission; the clutch C₇ is engaged and the clutch C₆ is disengagedduring low-speed transmission; and the clutch C₆ is engaged and theclutch C₇ is disengaged during high-speed transmission.

Beneficial effects: 1. The present invention is a multi-modehydro-mechanical hybrid transmission device that integrates hydraulictransmission, hydro-mechanical transmission, and mechanical transmissionand meets the requirements of different working conditions; 2. themulti-pump driven single-motor hydraulic system is employed to meet therequirements of different working conditions such as the directionchange of an input speed of a pump and the change of a displacementratio and the direction related thereto, and the system where multiplepumps work in turn can be used to obtain multiple flow combinations andprolong the use and maintenance cycle of the hydraulic system; 3.nonlinear full-range speed regulation involving the reciprocal of atransmission ratio and a displacement ratio is implemented throughhydro-mechanical split transmission, and linear staged stepless speedvariation involving the reciprocal of a transmission ratio and adisplacement ratio is implemented through combination of hydraulictransmission, hydro-mechanical convergence transmission, and mechanicaltransmission, to meet the requirements of different workingenvironments; 4. solutions of low-speed fine regulation and high-speedcoarse regulation are provided in each transmission type, and eachsolution has forward and reverse situations, to meet the requirements onspeed regulation range and speed regulation accuracy of different modesin the same type.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural diagram of the present invention; and

FIG. 2 is a table showing engagement/disengagement states ofmode-switching components in the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention is further described below with reference to theaccompanying drawings and specific embodiments, but the protection scopeof the present invention is not limited thereto.

As shown in FIG. 1, a multi-pump driven single-motor hydro-mechanicalhybrid transmission device includes an input shaft 1, a planetary gearsplit mechanism 2, a hydraulic transmission system 3, a planetary gearconvergence mechanism 4, and an output shaft 5. The input shaft 1 isconnected to the hydraulic transmission system 3 and the planetary gearconvergence mechanism 4 through the planetary gear split mechanism 2,and the hydraulic transmission system 3 and the planetary gearconvergence mechanism 4 are both connected to the output shaft 5. Thehydraulic transmission system 3 includes a multi-pump driving mechanism31, a fixed displacement motor mechanism 32, and a hydraulictransmission output mechanism 33. The multi-pump driving mechanism 31 isconnected to the fixed displacement motor mechanism 32, the fixeddisplacement motor mechanism 32 is connected to the planetary gearconvergence mechanism 4, and the fixed displacement motor mechanism 32is connected to the output shaft 5 through the hydraulic transmissionoutput mechanism 33.

The multi-pump driving mechanism 31 includes a first forward inputvariable displacement pump driving mechanism 311, a second forward inputvariable displacement pump driving mechanism 312, a first reverse inputvariable displacement pump driving mechanism 313, and a second reverseinput variable displacement pump driving mechanism 314. A reversingvalve V₄ 34 is arranged between the multi-pump driving mechanism 31 andthe fixed displacement motor mechanism 32.

The first forward input variable displacement pump driving mechanism 311includes a variable displacement pump P₁, a check valve V₃₁, apilot-operated relief valve V₂₂, and a solenoid valve V₁₁. The solenoidvalve V₁₁ controls a control pressure of the pilot-operated relief valveV₂₁, and the variable displacement pump P₁ is connected to the reversingvalve V₄ 34 through the check valve V₃₁.

The second forward input variable displacement pump driving mechanism312 includes a variable displacement pump P₂, a check valve V₃₂, apilot-operated relief valve V₂₂, and a solenoid valve V₁₂. The solenoidvalve V₁₂ controls a control pressure of the pilot-operated relief valveV₂₂, and the variable displacement pump P₂ is connected to the reversingvalve V₄ 34 through the check valve V₃₂.

The first reverse input variable displacement pump driving mechanism 313includes a variable displacement pump P₃, a check valve V₃₃, apilot-operated relief valve V₂₃, and a solenoid valve V₁₃. The solenoidvalve V₁₃ controls a control pressure of the pilot-operated relief valveV₂₃, and the variable displacement pump P₃ is connected to the reversingvalve V₄ 34 through the check valve V₃₃.

The second reverse input variable displacement pump driving mechanism314 includes a variable displacement pump P₄, a check valve V₃₄, apilot-operated relief valve V₂₄, and a solenoid valve V₁₄. The solenoidvalve V₁₄ controls a control pressure of the pilot-operated relief valveV₂₄, and the variable displacement pump P₄ is connected to the reversingvalve V₄ 34 through the check valve V₃₄.

A jackshaft 6 is arranged between the planetary gear split mechanism 2and the planetary gear convergence mechanism 4.

The planetary gear split mechanism 2 includes a split mechanismfront-sun gear 21, a split mechanism front-planet carrier 22, a splitmechanism rear-sun gear 23, a split mechanism rear-planet carrier 24,and a split mechanism shared ring gear 25. The input shaft 1 isconnected to the split mechanism front-sun gear 21 and the splitmechanism rear-planet carrier 24. A clutch C₁ is arranged between thesplit mechanism rear-planet carrier 24 and the split mechanism rear-sungear 23. A clutch C₂ is arranged between the split mechanismfront-planet carrier 22 and the jackshaft 6. A clutch C₃ is arrangedbetween the split mechanism rear-sun gear 23 and the jackshaft 6. Aclutch C₄ is arranged between the split mechanism shared ring gear 25and the hydraulic transmission system 3.

The planetary gear convergence mechanism 4 includes a convergencemechanism shared sun gear 41, a convergence mechanism front-planetcarrier 42, a convergence mechanism front-ring gear 43, a convergencemechanism rear-planet carrier 44, and a convergence mechanism rear-ringgear 45. The jackshaft 6 is connected to the convergence mechanismfront-planet carrier 42, and the convergence mechanism front-planetcarrier 42 is connected to the convergence mechanism rear-ring gear 45.A clutch C₅ is arranged between the jackshaft 6 and the convergencemechanism shared sun gear 41. A clutch C₆ is arranged between theconvergence mechanism front-ring gear 43 and the output shaft 5. Aclutch C₇ is arranged between the convergence mechanism rear-planetcarrier 44 and the output shaft 5.

A clutch C₈ is arranged between the hydraulic transmission outputmechanism 33 and the output shaft 5.

A brake B₁ is arranged between the fixed displacement motor mechanism 32and the hydraulic transmission output mechanism 33.

As shown in FIG. 2, a control method of the multi-pump drivensingle-motor hydro-mechanical hybrid transmission device implementsswitching among forward or reverse and high or low speed transmissionmodes of four transmission types including hydraulic transmission,hydro-mechanical split transmission, hydro-mechanical convergencetransmission, and mechanical transmission through selection of theclutches, the brake, and the variable displacement pumps and combinationcontrol of the reversing valve.

In a transmission mode of forward hydraulic low-speed fine regulation,the clutch C₁, the clutch C₄, and the clutch C₈ are engaged while theclutch C₂, the clutch C₃, the clutch C₅, the clutch C₆, the clutch C₇,and the brake B₁ are disengaged, the reversing valve V₄ 34 is switchedto a right position, and the first reverse input variable displacementpump driving mechanism 313 is switched on; power passes through theinput shaft 1, the planetary gear split mechanism 2, the first reverseinput variable displacement pump driving mechanism 313, the rightposition of the reversing valve V₄ 34, the fixed displacement motormechanism 32, and the hydraulic transmission output mechanism 33 and isoutput from the output shaft 5; in this case, the input-outputrelationship satisfies the following formula:

$\begin{matrix}{{n_{o} = {\frac{e}{i_{1}i_{9}}n_{I}}},{e \in \lbrack 0.05\rbrack}} & (1)\end{matrix}$

wherein n_(o) is an output speed, n₁ is an input speed, e is adisplacement ratio of the hydraulic system, and i is a transmissionratio of a related gear pair.

In a transmission mode of forward hydraulic medium-speed regulation, theclutch C₁, the clutch C₄, and the clutch C₈ are engaged while the clutchC₂, the clutch C₃, the clutch C₅, the clutch C₆, the clutch C₇, and thebrake B₁ are disengaged, the reversing valve V₄ 34 is switched to theright position, and the second reverse input variable displacement pumpdriving mechanism 314 is switched on; power passes through the inputshaft 1, the planetary gear split mechanism 2, the second reverse inputvariable displacement pump driving mechanism 314, the right position ofthe reversing valve V₄ 34, the fixed displacement motor mechanism 32,and the hydraulic transmission output mechanism 33 and is output fromthe output shaft 5; in this case, the input-output relationshipsatisfies the following formula:

$\begin{matrix}{{n_{o} = {\frac{e}{i_{1}i_{9}}n_{I}}},{e \in {\left\lbrack {0,1.0} \right\rbrack.}}} & (2)\end{matrix}$

In a transmission mode of forward hydraulic high-speed coarseregulation, the clutch C₁, the clutch C₄, and the clutch C₈ are engagedwhile the clutch C₂, the clutch C₃, the clutch C₅, the clutch C₆, theclutch C₇, and the brake B₁ are disengaged, the reversing valve V₄ 34 isswitched to the right position, and the first reverse input variabledisplacement pump driving mechanism 313 and the second reverse inputvariable displacement pump driving mechanism 314 are both switched on;power passes through the input shaft 1, the planetary gear splitmechanism 2, the first reverse input variable displacement pump drivingmechanism 313 and the second reverse input variable displacement pumpdriving mechanism 314, the right position of the reversing valve V₄ 34,the fixed displacement motor mechanism 32, and the hydraulictransmission output mechanism 33 and is output from the output shaft 5;in this case, the input-output relationship satisfies the followingformula:

$\begin{matrix}{{n_{o} = {\frac{e}{i_{1}i_{9}}n_{I}}},{e \in {\left\lbrack {0,1.5} \right\rbrack.}}} & (3)\end{matrix}$

In a transmission mode of reverse hydraulic low-speed fine regulation,the clutch C₁, the clutch C₄, and the clutch C₈ are engaged while theclutch C₂, the clutch C₃, the clutch C₅, the clutch C₆, the clutch C₇,and the brake B₁ are disengaged, the reversing valve V₄ 34 is switchedto a left position, and the first reverse input variable displacementpump driving mechanism 313 is switched on; power passes through theinput shaft 1, the planetary gear split mechanism 2, the first reverseinput variable displacement pump driving mechanism 313, the leftposition of the reversing valve V₄ 34, the fixed displacement motormechanism 32, and the hydraulic transmission output mechanism 33 and isoutput from the output shaft 5; in this case, the input-outputrelationship satisfies the following formula:

$\begin{matrix}{{n_{o} = {\frac{e}{i_{1}i_{9}}n_{I}}},{e \in {\left\lbrack {{- 0.5},0} \right\rbrack.}}} & (4\;)\end{matrix}$

In a transmission mode of reverse hydraulic medium-speed regulation, theclutch C₁, the clutch C₄, and the clutch C₈ are engaged while the clutchC₂, the clutch C₃, the clutch C₅, the clutch C₆, the clutch C₇, and thebrake B₁ are disengaged, the reversing valve V₄ 34 is switched to theleft position, and the second reverse input variable displacement pumpdriving mechanism 314 is switched on; power passes through the inputshaft 1, the planetary gear split mechanism 2, the second reverse inputvariable displacement pump driving mechanism 314, the left position ofthe reversing valve V₄ 34, the fixed displacement motor mechanism 32,and the hydraulic transmission output mechanism 33 and is output fromthe output shaft 5; in this case, the input-output relationshipsatisfies the following formula:

$\begin{matrix}{{n_{o} = {\frac{e}{i_{1}i_{9}}n_{I}}},{e \in {\left\lbrack {{- 1.0},0} \right\rbrack.}}} & (5)\end{matrix}$

In a transmission mode of reverse hydraulic high-speed coarseregulation, the clutch C₁, the clutch C₄, and the clutch C₈ are engagedwhile the clutch C₂, the clutch C₃, the clutch C₅, the clutch C₆, theclutch C₇, and the brake B₁ are disengaged, the reversing valve V₄ 34 isswitched to the left position, and the first reverse input variabledisplacement pump driving mechanism 313 and the second reverse inputvariable displacement pump driving mechanism 314 are both switched on;power passes through the input shaft 1, the planetary gear splitmechanism 2, the first reverse input variable displacement pump drivingmechanism 313 and the second reverse input variable displacement pumpdriving mechanism 314, the left position of the reversing valve V₄ 34,the fixed displacement motor mechanism 32, and the hydraulictransmission output mechanism 33 and is output from the output shaft 5;in this case, the input-output relationship satisfies the followingformula:

$\begin{matrix}{{n_{o} = {\frac{e}{i_{1}i_{9}}n_{I}}},{e \in {\left\lbrack {{- 1.5},0} \right\rbrack.}}} & (6)\end{matrix}$

In a transmission mode of forward hydro-mechanical split low-speed fineregulation, the clutch C₃, the clutch C₄, the clutch C₅, and the clutchC₇ are engaged while the clutch C₁, the clutch C₂, the clutch C₆, theclutch C₈, and the brake B₁ are disengaged, the reversing valve V₄ 34 isswitched to the right position, and the second reverse input variabledisplacement pump driving mechanism 314 is switched on; thereby, theplanetary gear convergence mechanism 4 is fixedly connected as a whole,and power passes through the input shaft 1 to the split mechanismrear-planet carrier 23 and is split into two parts: one part of thepower is transmitted through the split mechanism shared ring gear 25,the clutch C₄, the second reverse input variable displacement pumpdriving mechanism 314, the right position of the reversing valve V₄ 34,and the fixed displacement motor mechanism 32 to the convergencemechanism shared sun gear 41, while the other part of the power istransmitted through the split mechanism rear-sun gear 23, the clutch C₃,and the jackshaft 6 to the convergence mechanism rear-ring gear 45; thetwo parts of the power are converged at the convergence mechanismrear-planet carrier 44 and then transmitted through the clutch C₇ andoutput from the output shaft 5; in this case, the input-outputrelationship satisfies the following formula:

$\begin{matrix}{{n_{o} = {\frac{k_{2} + 1}{{i_{4}i_{5}i_{7}i_{8}} + \frac{k_{2}i_{1}i_{2}i_{7}i_{8}}{e}}n_{I}}},{e \in \left\lbrack {0,1.0} \right\rbrack}} & (7)\end{matrix}$

wherein k is a characteristic parameter of a related planetary gear.

In a transmission mode of forward hydro-mechanical split high-speedcoarse regulation, the clutch C₃, the clutch C₄, the clutch C₅, and theclutch C₆ are engaged while the clutch C₁, the clutch C₂, the clutch C₇,the clutch C₈, and the brake B₁ are disengaged, the reversing valve V₄34 is switched to the right position, and the first reverse inputvariable displacement pump driving mechanism 313 and the second reverseinput variable displacement pump driving mechanism 314 are both switchedon; thereby, the planetary gear convergence mechanism 4 is fixedlyconnected as a whole, and power passes through the input shaft 1 to thesplit mechanism rear-planet carrier 23 and is split into two parts: onepart of the power is transmitted through the split mechanism shared ringgear 25, the clutch C₄, the first reverse input variable displacementpump driving mechanism 313 and the second reverse input variabledisplacement pump driving mechanism 314 that are connected in parallel,the right position of the reversing valve V₄ 34, and the fixeddisplacement motor mechanism 32 to the convergence mechanism shared sungear 41, while the other part of the power is transmitted through thesplit mechanism rear-sun gear 23, the clutch C₃, and the jackshaft 6 tothe convergence mechanism front-planet carrier 42; the two parts of thepower are converged at the convergence mechanism front-ring gear 43 andthen transmitted through the clutch C₆ and output from the output shaft5; in this case, the input-output relationship satisfies the followingformula:

$\begin{matrix}{{n_{o} = {\frac{k_{2} + 1}{{i_{4}i_{5}i_{6}i_{8}} + \frac{k_{2}i_{1}i_{2}i_{6}i_{8}}{e}}n_{I}}},{e \in {\left\lbrack {0,1.5} \right\rbrack.}}} & (8)\end{matrix}$

In a transmission mode of reverse hydro-mechanical split low-speed fineregulation, the clutch C₂, the clutch C₄, the clutch C₅, and the clutchC₇ are engaged while the clutch C₁, the clutch C₃, the clutch C₆, theclutch C₈, and the brake B₁ are disengaged, the reversing valve V₄ 34 isswitched to the right position, and the second forward input variabledisplacement pump driving mechanism 312 is switched on; thereby, theplanetary gear convergence mechanism 4 is fixedly connected as a whole,and power passes through the input shaft 1 to the split mechanismfront-sun gear 21 and is split into two parts: one part of the power istransmitted through the split mechanism shared ring gear 25, the clutchC₄, the second forward input variable displacement pump drivingmechanism 312, the right position of the reversing valve V₄ 34, and thefixed displacement motor mechanism 32 to the convergence mechanismshared sun gear 41, while the other part of the power is transmittedthrough the split mechanism front-planet carrier 22, the clutch C₂, andthe jackshaft 6 to the convergence mechanism rear-ring gear 45; the twoparts of the power are converged at the convergence mechanismrear-planet carrier 44 and then transmitted through the clutch C₇ andoutput from the output shaft 5; in this case, the input-outputrelationship satisfies the following formula:

$\begin{matrix}{{n_{o} = {\frac{1}{{\left( {k_{1} + 1} \right)i_{3}i_{7}i_{8}} + \frac{k_{1}i_{1}i_{2}i_{7}i_{8}}{e}}n_{I}}},{e \in {\left\lbrack {0,1.0} \right\rbrack.}}} & (9)\end{matrix}$

In a transmission mode of reverse hydro-mechanical split high-speedcoarse regulation, the clutch C₂, the clutch C₄, the clutch C₅, and theclutch C₆ are engaged while the clutch C₁, the clutch C₃, the clutch C₇,the clutch C₈, and the brake B₁ are disengaged, the reversing valve V₄34 is switched to the right position, and the first forward inputvariable displacement pump driving mechanism 311 and the second forwardinput variable displacement pump driving mechanism 312 are both switchedon; thereby, the planetary gear convergence mechanism 4 is fixedlyconnected as a whole, and power passes through the input shaft 1 to thesplit mechanism front-sun gear 21 and is split into two parts: one partof the power is transmitted through the split mechanism shared ring gear25, the clutch C₄, the first forward input variable displacement pumpdriving mechanism 311 and the second forward input variable displacementpump driving mechanism 312 that are connected in parallel, the rightposition of the reversing valve V₄ 34, and the fixed displacement motormechanism 32 to the convergence mechanism shared sun gear 41, while theother part of the power is transmitted through the split mechanismfront-planet carrier 22, the clutch C₂, and the jackshaft 6 to theconvergence mechanism front-planet carrier 42; the two parts of thepower are converged at the convergence mechanism front-ring gear 43 andthen transmitted through the clutch C₆ and output from the output shaft5; in this case, the input-output relationship satisfies the followingformula:

$\begin{matrix}{{n_{o} = {\frac{1}{{\left( {k + 1} \right)i_{3}i_{6}i_{8}} + \frac{k_{1}i_{1}i_{2}i_{6}i_{8}}{e}}n_{I}}},{e \in {\left\lbrack {0,1.5} \right\rbrack.}}} & (10)\end{matrix}$

In a transmission mode of forward hydro-mechanical convergence low-speedfine regulation, the clutch C₁, the clutch C₃, the clutch C₄, and theclutch C₇ are engaged while the clutch C₂, the clutch C₅, the clutch C₆,the clutch C₈, and the brake B₁ are disengaged, the reversing valve V₄34 is switched to the right position, and the first reverse inputvariable displacement pump driving mechanism 313 is switched on;thereby, the planetary gear split mechanism 2 is fixedly connected as awhole, and power passes through the input shaft 1 to the planetary gearsplit mechanism 2 and is split into two parts: one part of the power istransmitted through the clutch C₄, the first reverse input variabledisplacement pump driving mechanism 313, the right position of thereversing valve V₄ 34, and the fixed displacement motor mechanism 32 tothe convergence mechanism shared sun gear 41, while the other part ofthe power is transmitted through the clutch C₃ and the jackshaft 6 tothe convergence mechanism rear-ring gear 45; the two parts of the powerare converged at the convergence mechanism rear-planet carrier 44 andthen transmitted through the clutch C₇ and output from the output shaft5; in this case, the input-output relationship satisfies the followingformula:

$\begin{matrix}{{n_{o} = {\frac{\frac{k_{4}}{i_{4}i_{5}} + \frac{e}{i_{1}i_{2}}}{\left( {k_{4} + 1} \right)i_{7}i_{8}}n_{I}}},{e \in {\left\lbrack {0,0.5} \right\rbrack.}}} & (11)\end{matrix}$

In a transmission mode of forward hydro-mechanical convergencehigh-speed coarse regulation, the clutch C₁, the clutch C₃, the clutchC₄, and the clutch C₆ are engaged while the clutch C₂, the clutch C₅,the clutch C₇, the clutch C₈, and the brake B₁ are disengaged, thereversing valve V₄ 34 is switched to the right position, and the firstreverse input variable displacement pump driving mechanism 313 and thesecond reverse input variable displacement pump driving mechanism 314are both switched on; thereby, the planetary gear split mechanism 2 isfixedly connected as a whole, and power passes through the input shaft 1to the planetary gear split mechanism 2 and is split into two parts: onepart of the power is transmitted through the clutch C₄, the firstreverse input variable displacement pump driving mechanism 313 and thesecond reverse input variable displacement pump driving mechanism 314that are connected in parallel, the right position of the reversingvalve V₄ 34, and the fixed displacement motor mechanism 32 to theconvergence mechanism shared sun gear 41, while the other part of thepower is transmitted through the clutch C₃ and the jackshaft 6 to theconvergence mechanism front-planet carrier 42; the two parts of thepower are converged at the convergence mechanism front-ring gear 43 andthen transmitted through the clutch C₆ and output from the output shaft5; in this case, the input-output relationship satisfies the followingformula:

$\begin{matrix}{{n_{o} = {\frac{\frac{k_{3} + 1}{i_{4}i_{5}} - \frac{e}{i_{1}i_{2}}}{k_{3}i_{6}i_{8}}n_{I}}},{e \in {\left\lbrack {0,1.5} \right\rbrack.}}} & (12)\end{matrix}$

In a transmission mode of reverse hydro-mechanical convergence low-speedfine regulation, the clutch C₁, the clutch C₂, the clutch C₄, and theclutch C₇ are engaged while the clutch C₃, the clutch C₅, the clutch C₆,the clutch C₈ and the brake B₁ are disengaged, the reversing valve V₄ 34is switched to the left position, and the first reverse input variabledisplacement pump driving mechanism 313 is switched on; thereby, theplanetary gear split mechanism 2 is fixedly connected as a whole, andpower passes through the input shaft 1 to the planetary gear splitmechanism 2 and is split into two parts: one part of the power istransmitted through the clutch C₄, the first reverse input variabledisplacement pump driving mechanism 313, the left position of thereversing valve V₄ 34, and the fixed displacement motor mechanism 32 tothe convergence mechanism shared sun gear 41, while the other part ofthe power is transmitted through the clutch C₂ and the jackshaft 6 tothe convergence mechanism rear-ring gear 45; the two parts of the powerare converged at the convergence mechanism rear-planet carrier 44 andthen transmitted through the clutch C₇ and output from the output shaft5; in this case, the input-output relationship satisfies the followingformula:

$\begin{matrix}{{n_{o} = {\frac{{- \frac{k_{4}}{i_{3}}} + \frac{e}{i_{1}i_{2}}}{\left( {k_{4} + 1} \right)i_{7}i_{8}}n_{I}}},{e \in {\left\lbrack {{- 0.5},0} \right\rbrack.}}} & (13)\end{matrix}$

In a transmission mode of reverse hydro-mechanical convergencehigh-speed coarse regulation, the clutch C₁, the clutch C₂, the clutchC₄, and the clutch C₆ are engaged while the clutch C₃, the clutch C₅,the clutch C₇, the clutch C₈, and the brake B₁ are disengaged, thereversing valve V₄ 34 is switched to the left position, and the firstreverse input variable displacement pump driving mechanism 313 and thesecond reverse input variable displacement pump driving mechanism 314are both switched on; thereby, the planetary gear split mechanism 2 isfixedly connected as a whole, and power passes through the input shaft 1to the planetary gear split mechanism 2 and is split into two parts: onepart of the power is transmitted through the clutch C₄, the firstreverse input variable displacement pump driving mechanism 313 and thesecond reverse input variable displacement pump driving mechanism 314that are connected in parallel, the left position of the reversing valveV₄ 34, and the fixed displacement motor mechanism 32 to the convergencemechanism shared sun gear 41, while the other part of the power istransmitted through the clutch C₂ and the jackshaft 6 to the convergencemechanism front-planet carrier 42; the two parts of the power areconverged at the convergence mechanism front-ring gear 43 and thentransmitted through the clutch C₆ and output from the output shaft 5; inthis case, the input-output relationship satisfies the followingformula:

$\begin{matrix}{{n_{o} = {{- \frac{\frac{e}{i_{1}i_{2}} + \frac{k_{3} + 1}{i_{3}}}{k_{3}i_{6}i_{8}}}n_{I}}},{e \in {\left\lbrack {{- 1.5},0} \right\rbrack.}}} & (14)\end{matrix}$

In a forward mechanical low-speed transmission mode, the clutch C₁, theclutch C₃, the clutch C₇, and the brake B₁ are engaged while the clutchC₂, the clutch C₄, the clutch C₅, the clutch C₆, and the clutch C₈ aredisengaged, and the reversing valve V₄ 34 is in a middle position; powerpasses through the input shaft 1, the planetary gear split mechanism 2,the clutch C₃, the jackshaft 6, the convergence mechanism rear-ring gear45, the convergence mechanism rear-planet carrier 44, and the clutch C₇and is output from the output shaft 5; in this case, the input-outputrelationship satisfies the following formula:

$\begin{matrix}{n_{o} = {\frac{k_{4}}{\left( {k_{4} + 1} \right)i_{4}i_{5}i_{7}i_{8}}{n_{I}.}}} & (15)\end{matrix}$

In a forward mechanical high-speed transmission mode, the clutch C₁, theclutch C₃, the clutch C₆, and the brake B₁ are engaged while the clutchC₂, the clutch C₄, the clutch C₅, the clutch C₇, and the clutch C₈ aredisengaged, and the reversing valve V₄ 34 is in the middle position;power passes through the input shaft 1, the planetary gear splitmechanism 2, the clutch C₃, the jackshaft 6, the convergence mechanismfront-planet carrier 42, the convergence mechanism front-ring gear 43,and the clutch C₆ and is output from the output shaft 5; in this case,the input-output relationship satisfies the following formula:

$\begin{matrix}{n_{o} = {\frac{k_{3} + 1}{k_{3}i_{4}i_{5}i_{6}i_{8}}{n_{I}.}}} & (16)\end{matrix}$

In a reverse mechanical low-speed transmission mode, the clutch C₁, theclutch C₂, the clutch C₇, and the brake B₁ are engaged while the clutchC₃, the clutch C₄, the clutch C₅, the clutch C₆, and the clutch C₈ aredisengaged, and the reversing valve V₄ 34 is in the middle position;power passes through the input shaft 1, the planetary gear splitmechanism 2, the clutch C₂, the jackshaft 6, the convergence mechanismrear-ring gear 45, the convergence mechanism rear-planet carrier 44, andthe clutch C₇ and is output from the output shaft 5; in this case, theinput-output relationship satisfies the following formula:

$\begin{matrix}{n_{o} = {{- \frac{k_{4}}{\left( {k_{4} + 1} \right)i_{3}i_{7}i_{8}}}{n_{I}.}}} & (17)\end{matrix}$

In a forward mechanical high-speed transmission mode, the clutch C₁, theclutch C₂, the clutch C₆, and the brake B₁ are engaged while the clutchC₃, the clutch C₄, the clutch C₅, the clutch C₇, and the clutch C₈ aredisengaged, and the reversing valve V₄ 34 is in the middle position;power passes through the input shaft 1, the planetary gear splitmechanism 2, the clutch C₂, the jackshaft 6, the convergence mechanismfront-planet carrier 42, the convergence mechanism front-ring gear 43,and the clutch C₆ and is output from the output shaft 5; in this case,the input-output relationship satisfies the following formula:

$\begin{matrix}{n_{o} = {{- \frac{k_{3} + 1}{k_{3}i_{3}i_{6}i_{8}}}{n_{I}.}}} & (18)\end{matrix}$

In the formulas (1) to (18), i₁i₂=1, i₃=i₄i₅=1, i₁i₉=1, k₁=1.56,k₂=2.56, k₃=1.56, k₄=2.56, i₆i₈=1.76, i₇i₈=2.52.

Different pump-controlled motor mechanisms are selected according tospeed regulation range and speed regulation accuracy, and the multi-pumpdriving mechanism consisting of the first forward variable displacementpump P₁ of a small flow, the second forward variable displacement pumpP₂ of a large flow, the first reverse variable displacement pump P₃ of asmall flow, and the second reverse variable displacement pump P₄ of alarge flow that are connected in parallel is controlled by a programmedcontroller to supply oil to the system, thereby obtaining multiplecombinations in forward and reverse directions.

When the displacement ratio is required to fall in a range of|e|∈[0,0.5] and the measured input speed of the pump n_(P) is in aforward direction, only the first forward variable displacement pump P₁is working; if oil output by the first forward variable displacementpump P₁ passes through the right position of the three-position four-wayreversing valve V₄ 34 to drive the fixed displacement motor mechanism32, the output speed of the motor nu is in a range ofn_(M)∈[0,0.5]|n_(P)|; and if oil output by the first forward variabledisplacement pump P₁ passes through the left position of thethree-position four-way reversing valve V₄ 34 to drive the fixeddisplacement motor mechanism 32, the output speed of the motor n_(M) isin a range of n_(M)[−0.5,0]|n_(P)|.

When the displacement ratio is required to fall in a range of|e|∈[0,1.0] and the measured input speed of the pump n_(P) is in aforward direction, only the second forward variable displacement pump P₂is working; if oil output by the second forward variable displacementpump P₂ passes through the right position of the three-position four-wayreversing valve V₄ 34 to drive the fixed displacement motor mechanism32, the output speed of the motor n_(M) is in a range ofn_(M)∈[0,1.0]|n_(P)|; and if oil output by the second forward variabledisplacement pump P₂ passes through the left position of thethree-position four-way reversing valve V₄ 34 to drive the fixeddisplacement motor mechanism 32, the output speed of the motor nu is ina range of n_(M)∈[−1.0,0]|n_(P).

When the displacement ratio is required to fall in a range of|e|∈[0,1.5] and the measured input speed of the pump n_(P) is in aforward direction, the first forward variable displacement pump P₁ andthe second forward variable displacement pump P₂ are both working; ifoil output by the above two pumps passes through the right position ofthe three-position four-way reversing valve V₄ 34 to drive the fixeddisplacement motor mechanism 32, the output speed of the motor n_(M) isin a range of n_(M)∈[0,1.5]|n_(P)|; and if oil output by the above twopumps passes through the right position of the three-position four-wayreversing valve V₄ 34 to drive the fixed displacement motor mechanism32, the output speed of the motor n_(M) is in a range of n_(M)∈[−1.5,0]|n_(P)|.

When the displacement ratio is required to fall in a range of|e|∈[0,0.5] and the measured input speed of the pump n_(P) is in areverse direction, only the first reverse variable displacement pump P₃is working; if oil output by the first reverse variable displacementpump P₃ passes through the right position of the three-position four-wayreversing valve V₄ 34 to drive the fixed displacement motor mechanism32, the output speed of the motor n_(M) is in a range ofn_(M)∈[0,0.5]|n_(P)|; and if oil output by the first reverse variabledisplacement pump P₃ passes through the left position of thethree-position four-way reversing valve V₄ 34 to drive the fixeddisplacement motor mechanism 32, the output speed of the motor n_(M) isin a range of n_(M)∈[−0.5,0]|n_(P)|.

When the displacement ratio is required to fall in a range of|e|∈[0,1.0] and the measured input speed of the pump n_(P) is in areverse direction, only the second reverse variable displacement pump P₄is working; if oil output by the second reverse variable displacementpump P₄ passes through the right position of the three-position four-wayreversing valve V₄ 34 to drive the fixed displacement motor mechanism32, the output speed of the motor n_(M) is in a range ofn_(M)∈[0,1.0]|n_(P)|; and if oil output by the second reverse variabledisplacement pump P₄ passes through the left position of thethree-position four-way reversing valve V₄ 34 to drive the fixeddisplacement motor mechanism 32, the output speed of the motor n_(M) isin a range of n_(M)∈[−1.0,0]|n_(P)|.

When the displacement ratio is required to fall in a range of|e|∈[0,1.5] and the measured input speed of the pump n_(P) is in areverse direction, the first reverse variable displacement pump P₃ andthe second reverse variable displacement pump P₄ are both working; ifoil output by the above two pumps passes through the right position ofthe three-position four-way reversing valve V₄ 34 to drive the fixeddisplacement motor mechanism 32, the output speed of the motor n_(M) isin a range of n_(M)∈[0,1.5]|n_(P)|; and if oil output by the above twopumps passes through the left position of the three-position four-wayreversing valve V₄ 34 to drive the fixed displacement motor mechanism32, the output speed of the motor n_(M) is in a range ofn_(M)∈[−1.5,0]|n_(P)|.

Full-range speed regulation is implemented through hydro-mechanicalsplit transmission:

In the formula (7):

${n_{o} = {\frac{3.56}{2.52 + \frac{6.4512}{e}}n_{I}}},$

when e∈[0,1.0], n_(o)∈[0, 0.397]n_(l);

that is, a mode g of forward low-speed fine regulation is adopted,wherein the output speed is in a range of n_(o)∈[0, 0.397]n_(l);

in the formula (8):

${n_{o} = {\frac{3.56}{1.76 + \frac{4.5056}{e}}n_{I}}},$

when e∈[0, 1.5], n_(o)[0, 0.747]n_(l);

that is, a mode h of forward high-speed coarse regulation is adopted,wherein the output speed is in a range of n_(o)∈[0, 0.747]n_(l);

in the formula (9):

${n_{o} = {{- \frac{1}{6.4512 + \frac{3.9312}{e}}}n_{I}}},$

when e∈[0, 1.0], n_(o)[−0.096, 0]n_(l);

that is, a mode i of reverse low-speed fine regulation is adopted,wherein the output speed is in a range of n_(o)∈[−0.096, 0]n_(l);

in the formula (10):

${n_{o} = {{- \frac{1}{4.5056 + \frac{2.7456}{e}}}n_{I}}},$

when e∈[0, 1.5], n_(o)∈[−0.158, 0]n_(l);

that is, a mode j of reverse high-speed coarse regulation is adopted,wherein the output speed is in a range of n_(o)∈[−0.158, 0]n_(l).

Staged stepless speed regulation is implemented through hydraulictransmission, hydro-mechanical convergence transmission, and mechanicaltransmission:

The formula (1) n_(o)=en_(l) and the formula (11)

$n_{o} = {\frac{2.56 + e}{8.9712}n_{I}}$

are associated, wherein

1. when e=0.321∈[0, 0.5], a common point n_(o)=0.321n_(l) is obtained;

2. as for the formula (11), n_(o)[0.285, 0.341]n_(l);

3. when e=0, a mechanical gear is obtained, and the formula (15)n_(o)=0.285n_(l) is satisfied;

that is, a mode a is adopted for hydraulic forward low-speed startup;when n_(o)=0.321n_(l), the mode is switched to a mode k; with thechanges of e, efficient stepless speed variation is implemented; andwhen e=0, the mode is switched to a mode o;

the formula (3) n_(o)=en_(l) and the formula (12)

$n_{o} = {\frac{2.56 - e}{2.7456}n_{I}}$

are associated, wherein

1. when e=0.683∈[0, 1.5], a common point n_(o)=0.683n_(l) is obtained;

2. as for the formula (12), n_(o)[0.386, 0.932]n_(l);

3. when e=0, a mechanical gear is obtained, and the formula (16)n_(o)=0.932n_(l) is satisfied;

that is, a mode c is adopted for hydraulic forward high-speed startup;when n_(o)=0.683n_(l), the mode is switched to a mode l; with thechanges of e, efficient stepless speed variation is implemented; andwhen e=0, the mode is switched to a mode p;

the formula (4) n_(o)=en_(l) and the formula (13)

$n_{o} = {\frac{{- 2.56} + e}{8.9712}n_{I}}$

are associated, wherein

1. when e=−0.321∈[−0.5, 0], a common point n_(o)=−0.321n_(l) isobtained;

2. as for the formula (13), n_(o)∈[−0.341, −0.285]n_(l);

3. when e=0, a mechanical gear is obtained, and the formula (17)n_(o)=−0.285n_(l) is satisfied;

that is, a mode d is adopted for hydraulic reverse low-speed startup;when n_(o)=−0.321n_(l), the mode is switched to a mode m; with thechanges of e, efficient stepless speed variation is implemented; andwhen e=0, the mode is switched to a mode q;

the formula (6) n_(o)=en_(l) and the formula (14)

$n_{o} = {\frac{2.56 + e}{2.7456}n_{I}}$

are associated, wherein

1. when e=−0.683∈[−1.5, 0], a common point n_(o)=−0.683n_(l) isobtained;

2. as for the formula (14), n_(o)∈[−0.932, −0.386]n_(l);

3. when e=0, a mechanical gear is obtained, and the formula (18)n_(o)=−0.932n_(l) is satisfied;

that is, a mode f is adopted for hydraulic reverse high-speed startup;when n_(o)=−0.683n_(l), the mode is switched to a mode n; with thechanges of e, efficient stepless speed variation is implemented; andwhen e=0, the mode is switched to a mode r.

The above descriptions are preferred embodiments of the presentinvention, and are not intended to limit the present invention. Anyobvious improvements, replacements, or modifications made by personsskilled in the art without departing from the essence of the presentinvention shall fall within the protection scope of the presentinvention.

What is claimed is:
 1. A multi-pump driven single-motor hydro-mechanicalhybrid transmission device, comprising an input shaft, a planetary gearsplit mechanism, a hydraulic transmission system, a planetary gearconvergence mechanism, and an output shaft; wherein the input shaft isconnected to the hydraulic transmission system and the planetary gearconvergence mechanism through the planetary gear split mechanism; thehydraulic transmission system and the planetary gear convergencemechanism are both connected to the output shaft; the hydraulictransmission system comprises a multi-pump driving mechanism, a fixeddisplacement motor mechanism, and a hydraulic transmission outputmechanism; wherein the multi-pump driving mechanism is connected to thefixed displacement motor mechanism, the fixed displacement motormechanism is connected to the planetary gear convergence mechanism, andthe fixed displacement motor mechanism is connected to the output shaftthrough the hydraulic transmission output mechanism; the multi-pumpdriving mechanism comprises two groups of variable displacement pumpdriving mechanisms, wherein the two groups of variable displacement pumpdriving mechanisms are connected in parallel and have opposite inputdirections, and the two groups of variable displacement pump drivingmechanisms comprise a first forward input variable displacement pumpdriving mechanism, a second forward input variable displacement pumpdriving mechanism, a first reverse input variable displacement pumpdriving mechanism, and a second reverse input variable displacement pumpdriving mechanism; a reversing valve is arranged between the multi-pumpdriving mechanism and the fixed displacement motor mechanism; the firstforward input variable displacement pump driving mechanism comprises afirst variable displacement pump, a first check valve, a firstpilot-operated relief valve, and a first solenoid valve; wherein thefirst solenoid valve controls a control pressure of the firstpilot-operated relief valve, and the first variable displacement pump isconnected to the reversing valve through the first check valve; thesecond forward input variable displacement pump driving mechanismcomprises a second variable displacement pump, a second check valve, asecond pilot-operated relief valve, and a second solenoid valve; whereinthe second solenoid valve controls a control pressure of the secondpilot-operated relief valve, and the second variable displacement pumpis connected to the reversing valve through the second check valve; thefirst reverse input variable displacement pump driving mechanismcomprises a third variable displacement pump, a third check valve, athird pilot-operated relief valve, and a third solenoid valve; whereinthe third solenoid valve controls a control pressure of the thirdpilot-operated relief valve, and the third variable displacement pump isconnected to the reversing valve through the third check valve; thesecond reverse input variable displacement pump driving mechanismcomprises a fourth variable displacement pump, a fourth check valve, afourth pilot-operated relief valve, and a fourth solenoid valve; whereinthe fourth solenoid valve controls a control pressure of the fourthpilot-operated relief valve, and the fourth variable displacement pumpis connected to the reversing valve through the fourth check valve; ajackshaft is arranged between the planetary gear split mechanism and theplanetary gear convergence mechanism; the planetary gear split mechanismcomprises a split mechanism front-sun gear, a split mechanismfront-planet carrier, a split mechanism rear-sun gear, a split mechanismrear-planet carrier, and a split mechanism shared ring gear; wherein theinput shaft is connected to the split mechanism front-sun gear and thesplit mechanism rear-planet carrier; a first clutch is arranged betweenthe split mechanism rear-planet carrier and the split mechanism rear-sungear; a second clutch is arranged between the split mechanismfront-planet carrier and the jackshaft; a third clutch is arrangedbetween the split mechanism rear-sun gear and the jackshaft; a fourthclutch is arranged between the split mechanism shared ring gear and thehydraulic transmission system; the planetary gear convergence mechanismcomprises a convergence mechanism shared sun gear, a convergencemechanism front-planet carrier, a convergence mechanism front-ring gear,a convergence mechanism rear-planet carrier, and a convergence mechanismrear-ring gear; wherein the jackshaft is connected to the convergencemechanism front-planet carrier, and the convergence mechanismfront-planet carrier is connected to the convergence mechanism rear-ringgear; a fifth clutch is arranged between the jackshaft and theconvergence mechanism shared sun gear; a sixth clutch is arrangedbetween the convergence mechanism front-ring gear and the output shaft;a seventh clutch is arranged between the convergence mechanismrear-planet carrier and the output shaft; an eighth clutch is arrangedbetween the hydraulic transmission output mechanism and the outputshaft; and a brake is arranged between the fixed displacement motormechanism and the hydraulic transmission output mechanism.
 2. (canceled)3. (canceled)
 4. (canceled)
 5. A control method of the multi-pump drivensingle-motor hydro-mechanical hybrid transmission device according toclaim 1, comprising: switching among a forward mode or a reverse modeand a high speed transmission mode or a low speed transmission mode offour transmission types comprising hydraulic transmission,hydro-mechanical split transmission, hydro-mechanical convergencetransmission, and mechanical transmission through g selection of thefirst clutch, the second clutch, the third clutch, the fourth clutch,the fifth clutch, the sixth clutch, the seventh clutch, the eighthclutch, the brake, the first variable displacement pump, the secondvariable displacement pump, the third variable displacement pump and thefourth variable displacement pump, and a combination control of thereversing valve; wherein in the hydraulic transmission, the firstclutch, the fourth clutch, and the eighth clutch are engaged while thesecond clutch, the third clutch, the fifth clutch, the sixth clutch, theseventh clutch, and the brake are disengaged; power passes through theinput shaft, the planetary gear split mechanism, and the hydraulictransmission system and the power is output from the output shaft; whenthe first clutch is engaged, the split mechanism rear-planet carrier andthe split mechanism rear-sun gear of the planetary gear split mechanismare interlocked, the split mechanism rear-planet carrier and the splitmechanism rear-sun gear rotate as a whole, and the power is transmittedthrough the split mechanism shared ring gear to the fourth clutch; andwhen the fourth clutch is engaged, the power is transmitted through thefourth clutch to the multi-pump driving mechanism, the fixeddisplacement motor mechanism, and the hydraulic transmission outputmechanism of the hydraulic transmission system, and the power is finallytransmitted through the eighth clutch and the power is output from theoutput shaft; in the hydro-mechanical split transmission, the fourthclutch and the fifth clutch are engaged while the first clutch, theeighth clutch, and the brake are disengaged; the power passes throughthe input shaft to the planetary gear split mechanism and the power issplit into two parts at the planetary gear split mechanism into thehydraulic transmission system and the jackshaft, and the two parts ofthe power are converged at the planetary gear convergence mechanism andthen the two parts of the power are output from the output shaft; in thehydro-mechanical convergence transmission, the first clutch and thefourth clutch are engaged while the fifth clutch, the eighth clutch, andthe brake are disengaged; the power passes through the input shaft tothe planetary gear split mechanism and the power is split into the twoparts at the planetary gear split mechanism into the hydraulictransmission system and the jackshaft, and the two parts of the powerare converged at the planetary gear convergence mechanism and then thetwo parts of the power are output from the output shaft; in themechanical transmission, the first clutch and the brake are engagedwhile the fourth clutch, the fifth clutch, and the eighth clutch aredisengaged, and the reversing valve is in a middle position; the powersequentially passes through the input shaft, the planetary gear splitmechanism, the jackshaft, and the planetary gear convergence mechanismand the power is then output from the output shaft.
 6. The controlmethod of the multi-pump driven single-motor hydro-mechanical hybridtransmission device according to claim 5, wherein in the hydraulictransmission, the reversing valve is switched to a right position duringforward transmission; the reversing valve is switched to a left positionduring reverse transmission; the first reverse input variabledisplacement pump driving mechanism is switched on during low-speed fineregulation; the second reverse input variable displacement pump drivingmechanism is switched on during medium-speed regulation; and the firstreverse input variable displacement pump driving mechanism and thesecond reverse input variable displacement pump driving mechanism areboth switched on during high-speed coarse regulation.
 7. The controlmethod of the multi-pump driven single-motor hydro-mechanical hybridtransmission device according to claim 5, wherein in thehydro-mechanical split transmission, the reversing valve is switched toa right position; the third clutch is engaged and the second clutch isdisengaged during forward transmission; the second clutch is engaged andthe third clutch is disengaged during reverse transmission; the seventhclutch is engaged and the sixth clutch is disengaged during low-speedfine regulation; the sixth clutch is engaged and the seventh clutch isdisengaged during high-speed coarse regulation; the second reverse inputvariable displacement pump driving mechanism is switched on duringforward low-speed fine regulation; the first reverse input variabledisplacement pump driving mechanism and the second reverse inputvariable displacement pump driving mechanism are both switched on duringforward high-speed coarse regulation; the second forward input variabledisplacement pump driving mechanism is switched on during reverselow-speed fine regulation; and the first forward input variabledisplacement pump driving mechanism and the second forward inputvariable displacement pump driving mechanism are both switched on duringreverse high-speed coarse regulation.
 8. The control method of themulti-pump driven single-motor hydro-mechanical hybrid transmissiondevice according to claim 5, wherein in the hydro-mechanical convergencetransmission, the reversing valve is switched to a right position, thethird clutch is engaged, and the second clutch is disengaged duringforward transmission; the reversing valve is switched to a leftposition, the econ clutch is engaged, and the third clutch is disengagedduring reverse transmission; the first reverse input variabledisplacement pump driving mechanism is switched on, the seventh clutchis engaged, and the sixth clutch is disengaged during low-speed fineregulation; and the first reverse input variable displacement pumpdriving mechanism and the second reverse input variable displacementpump driving mechanism are both switched on, the sixth clutch isengaged, and the seventh clutch is disengaged during high-speed coarseregulation.
 9. The control method of the multi-pump driven single-motorhydro-mechanical hybrid transmission device according to claim 5,wherein in the mechanical transmission, the third clutch is engaged andthe second clutch is disengaged during forward transmission; the secondclutch is engaged and the third clutch is disengaged during reversetransmission; the seventh clutch is engaged and the sixth clutch isdisengaged during low-speed transmission; and the sixth clutch isengaged and the seventh clutch is disengaged during high-speedtransmission.